Dysfunctional immune response in the COVID-19 patients is a recurrent theme impacting symptoms and mortality, yet the detailed understanding of pertinent immune cells is not complete. We applied single-cell RNA sequencing to 284 samples from 196 COVID-19 patients and controls and created a comprehensive immune landscape with 1.46 million cells. The large dataset enabled us to identify that different peripheral immune subtype changes were associated with distinct clinical features including age, sex, severity, and disease stages of COVID-19. SARS-CoV-2 RNAs were found in diverse epithelial and immune cell types, accompanied by dramatic transcriptomic changes within viral positive cells. Systemic up-regulation of S100A8/A9, mainly by megakaryocytes and monocytes in the peripheral blood, may contribute to the cytokine storms frequently observed in severe patients. Our data provide a rich resource for understanding the pathogenesis and developing effective therapeutic strategies for COVID-19.

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5-Aminolevulinic acid (ALA), a nonprotein amino acid involved in tetrapyrrole synthesis, has been widely applied in agriculture, medicine, and food production. Many engineered metabolic pathways have been constructed; however, the production yields are still low. In this study, several 5-aminolevulinic acid synthases (ALASs) from different sources were evaluated and compared with respect to their ALA production capacities in an engineered Corynebacterium glutamicum CgS1 strain that can accumulate succinyl-coenzyme A (CoA). A codon-optimized ALAS from Rhodobacter capsulatus SB1003 displayed the best potential. Recombinant strain CgS1/pEC-SB produced 7.6 g/liter ALA using a mineral salt medium in a fed-batch fermentation mode. Employing two-stage fermentation, 12.46 g/liter ALA was produced within 17 h, with a productivity of 0.73 g/liter/h, in recombinant C. glutamicum. Through overexpression of the heterologous nonspecific ALA exporter RhtA from Escherichia coli, the titer was further increased to 14.7 g/liter. This indicated that strain CgS1/pEC-SB-rhtA holds attractive industrial application potential for the future. IMPORTANCEIn this study, a two-stage fermentation strategy was used for production of the value-added nonprotein amino acid 5-aminolevulinic acid from glucose and glycine in a generally recognized as safe (GRAS) host, Corynebacterium glutamicum. The ALA titer represented the highest in the literature, to our knowledge. This high production capacity, combined with the potential easy downstream processes, made the recombinant strain an attractive candidate for industrial use in the future.A s the common precursor of tetrapyrroles such as porphyrin, heme, vitamin B 12 , and chlorophyll, 5-aminolevulinic acid (ALA) has been reported to be effective in tumor-localizing and photodynamic therapy for various diseases (1-3). ALA can also be used as a selective biodegradable herbicide and insecticide or an adversity resistance and growth-accelerating agent in agriculture (4, 5).In living organisms, two kinds of metabolic pathways have been described for ALA biosynthesis (Fig. 1). One is the C 5 pathway, which occurs in algae, higher plants, and many bacteria, including Escherichia coli and archaea. The C 5 pathway involves the following three enzymatic activities: glutamyl-tRNA synthetase (GluRS) (encoded by gltX), a NADPH-dependent glutamyl-tRNA reductase (HemA, encoded by hemA), and a glutamate-1-semialdehyde aminotransferase (HemL, encoded by hemL). The other is the C 4 pathway, which is present in birds, mammals, yeast, and purple non-sulfur-photosynthetic bacteria. In this pathway, ALA is formed through one-step catalysis by 5-aminolevulinic acid synthase (ALAS), which condenses glycine and succinyl-coenzyme A (CoA), an intermediate of the tricarboxylic acid (TCA) cycle.In E. coli, the native pathway for ALA biosynthesis is the C 5 pathway, which is tightly regulated by feedback inhibition of the end product heme (6). Previously, we developed a strategy to produce ALA in recombinant E. coli vi...

Biomedical application potentials of carbon nanotubes-based materials have been investigated intensively in recent years; however, characterization and metrology are still facing great technical challenges when the materials are intended to be used as carriers for therapeutics in aqueous solutions. Systematic characterization on the dispersing carbon nanotubes is urgently required and therefore of significance. In this paper multiwalled carbon nanotubes (MWCNTs) with different average lengths or with different oxidation degrees were dispersed in water and characterized systematically by applying UV spectroscopy, SEM, DLS, TGA, XPS, and FTIR. In particular, the characteristic absorption of the carbon nanotubes was analyzed using resolution-fitting technique to establish relations of wavelength and absorption intensity to the size distribution and surface chemistry. Results indicated that the absorption spectra of MWCNTs could reflect the variation of surface chemistry and length distribution of carbon nanotubes dispersed in water by combining with the other measurements. A vascular endothelium cell line was taken as a model to figure out association between physicochemical features and cytotoxicity of the carbon nanotubes. It was showed that the multiwalled carbon nanotubes with different oxidation degrees and similar length distribution exhibited different interaction files to the cells proliferation in a manner of time dependence and concentration dependence.

In this work the effects of four different multiwalled carbon nanotubes (MWCNTs), including long carboxylated (L-COOH), short carboxylated (S-COOH), long aminated (L-NH2) and short aminated (S-NH2) ones, on the integrity of red blood cells, coagulation kinetics and activation of platelets were investigated with human whole blood. We found that the four MWCNTs induced different degrees of red blood cell damage as well as a mild level of platelet activation (10–25%). L-COOH and L-NH2 induced a higher level of platelet activation than S-COOH and S-NH2 respectively; meanwhile L-NH2 caused marked reductions in platelet viability. The presence of the four MWCNTs led to earlier fibrin formation, L-NH2 increased the clots hardness significantly, while L-COOH and S-NH2 made the clots become softer. It was concluded that the four MWCNTs affected blood coagulation process and the clots mechanical properties; they also altered the integrity of the red blood cells and the viability of the platelets, as well as induced platelets activation. The effects of MWCNTs depended on the size and chemistry of the nanotubes and the type of cells they contacted.

The aim of this work was to probe the biodistribution and toxic effects of silver nanoparticles (NPs) with powerful anti-bacterial and anti-virus activities. For this purpose, novel silver NPs with gold nanorod (NR) core and silver shell (Au@Ag NRs) were developed and employed as a model material. The inner gold core provided an excellent internal reference for tracking the NRs in vivo. After subcutaneous injection of Au@Ag NRs, silver and gold contents in the subcutis and organs were examined by inductively coupled plasma mass spectrometry at different time points within 28 days. Histological analysis, physiological function and complement faction 3 (C3) and 5a (C5a) measurement were performed over time to reveal the toxic effect of Au@Ag NRs in vivo. Experimental results showed that majority of the Au@Ag NRs remained in the injection site except for a small amount migrating into the lymph nodes. The silver shell was dissolved in the subcutaneous tissue and released silver ions rapidly, which resulted in detectable silver accumulation in most of the organs. The accumulated silver ions in the kidney not only interacted with the kidney cells membrane but also induced a rapid increase of complement fraction C3 followed by a significant consumption and C3a and C5a production significantly in the serum, which resulted in kidney oxidative damage and eventually led to the morphological changes and filtration function impairment of the glomerulus. The released silver ions also caused oxidative injury of subcutaneous tissue in the injection site.

Epigenetic regulations play crucial roles in leukemogenesis and leukemia progression. SUV39H1 is the dominant H3K9 methyltransferase in the hematopoietic system, and its expression declines with aging. However, the role of SUV39H1 via its-mediated repressive modification H3K9me3 in leukemogenesis/leukemia progression remains to be explored. We found that SUV39H1 was down-regulated in a variety of leukemias, including MLL-r AML, as compared with normal individuals. Decreased levels of Suv39h1 expression and genomic H3K9me3 occupancy were observed in LSCs from MLL-r-induced AML mouse models in comparison with that of hematopoietic stem/progenitor cells. Suv39h1 overexpression increased leukemia latency and decreased the frequency of LSCs in MLL-r AML mouse models, while Suv39h1 knockdown accelerated disease progression with increased number of LSCs. Increased Suv39h1 expression led to the inactivation of Hoxb13 and Six1, as well as reversion of Hoxa9/Meis1 downstream target genes, which in turn decelerated leukemia progression. Interestingly, Hoxb13 expression is up-regulated in MLL-AF9-induced AML cells, while knockdown of Hoxb13 in MLL-AF9 leukemic cells significantly prolonged the survival of leukemic mice with reduced LSC frequencies. Our data revealed that SUV39H1 functions as a tumor suppressor in MLL-AF9-induced AML progression. These findings provide the direct link of SUV39H1 to AML development and progression.

Macrophages are one of the most important types of immune effector cells and are closely associated with tumor progression and metastasis. In this work, we investigated the influences of oxidized multiwalled carbon nanotubes (o-MWCNT) on macrophages that are resting in the normal subcutis tissue or in the tumor microenvironment in vivo as well as on the macrophage cell line of RAW 264.7 treated with combination of IL4, IL10 and IL13 in vitro. The o-MWCNT were characterized with SEM, DLS, FTIR, TGA, and UV-vis-NIR spectroscopy, and their effects on the RWA 264.7 cell line and breast cancer tumor-bearing mice were analyzed using the MTS assay, flow cytometry analysis, and histological and immunohistochemical observations. Our experimental results showed that subcutaneously injected o-MWCNT not only induced phagocytosis of the local resident macrophages, but also competitively recruited macrophages from other tissues. These interactions resulted in macrophage reduction and decreased vessel density around the tumor mass, which together inhibited tumor progression and metastasis in the lung. In the cell line model, the o-MWCNT inhibited the ability of the interleukin treated RAW macrophages to promote tumor cell migration as well as decreased their proliferation rate.